1. Field of the Invention
The present invention relates to an operation error verification method for a pattern writing apparatus, and a generation apparatus of operation error verification data for a pattern writing apparatus. For example, it relates to an operation error verification method for an electron beam pattern writing apparatus, and a generation apparatus of operation error verification data for an electron beam pattern writing apparatus.
2. Description of Related Art
Microlithography technology which forwards miniaturization of semiconductor devices is extremely important, because only this process performs forming a pattern in semiconductor manufacturing processes. In recent years, with an increase in high integration and large capacity of LSI, a critical dimension of a circuit required for semiconductor elements is becoming narrower and narrower. In order to form a desired circuit pattern on these semiconductor devices, a high precision master pattern (also called a mask or a reticle) is needed. Then, as the electron beam technology for writing or “drawing” a pattern has excellent resolution intrinsically, it is used for manufacturing such high precision master patterns.
FIG. 22 shows a schematic diagram for explaining operations of a conventional variable-shaped electron beam pattern writing apparatus. The variable-shaped electron beam (EB) pattern writing apparatus operates as follows. As shown in the figure, the pattern writing apparatus includes two aperture plates. A first or “upper” aperture plate 410 has an opening or “hole” 411 in the shape of a rectangle for shaping an electron beam 442. This shape of the rectangular opening may also be a square, a rhombus, a rhomboid, etc. A second or “lower” aperture plate 420 has a specially shaped opening 421 for shaping the electron beam 442 having passed through the opening 411 of the first aperture plate 410 into a desired rectangle. The electron beam 442 that left a charged particle source 430 and has passed through the opening 411 is deflected by a deflector. Then, the electron beam 442 passes through part of the specially shaped opening 421 of the second aperture plate 420, and reaches a target workpiece 440 mounted on a stage that is continuously moving in a predetermined direction (e.g. X-axis direction). In other words, a rectangular shape capable of passing through both of the opening 411 and the specially shaped opening 421 is written or “drawn” in a pattern writing area of the target workpiece 440 mounted on the stage. This method of writing or “forming” a given variable shape by letting beams pass through both of the opening 411 and the specially shaped opening 421 is called a variable shaped beam system.
When performing electron beam writing or “drawing”, first, the layout of a semiconductor integrated circuit is designed and its layout data is generated. Then, data of the chips satisfying some conditions in the layout data is merged to reconstruct the layout data. This process is defined as a chip merge process. The layout data for which the chip merge process has been performed is converted to generate writing data used in the electron beam pattern writing apparatus. Based on the writing data, a figure is divided into a shot size for actually shooting electron beams to write.
As a technique for generating exposure data to be input into an exposure apparatus (pattern writing apparatus), serving as a pre-step in manufacturing a mask, the following is disclosed: First, design data is divided into a plurality of processing units to perform parallel processing. Then, if an error arises in data conversion in one of the parallel processing, reprocessing is performed only for the data in which the error occurred, and data normally converted is used as it is. (Refer to, e.g., Japanese Published Unexamined Patent Application No. 5-249651 (JP-A-5-249651))
In this case, a writing error may be generated during the procedure from inputting the layout data into the pattern writing apparatus to inspecting the target workpiece on which a figure pattern has been written. If such a writing error arises when starting writing by the pattern writing apparatus, the easiest method for performing reproduction for inspection is to use completely the same data. However, if the processing time from starting writing to finding out an error generation point is long, there is a problem that the inspection of the error takes extremely long time.